#include <stdio.h>
#include <time.h> 
#include <math.h>
long add1(long n)     
{
	long i, sum = 0;
	for (i = 1; i <= n; i++)
		sum += i;
	return sum;
}
void AddTime1(long n) 
{
	clock_t t;
	long sum;
	t = clock();
    sum = add1(n);
    t = clock()-t;
	printf("方法1:\n");
	printf("  结果:1～%d之和:%ld\n", n, sum);
	printf("  用时:%lf秒\n", ((float)t) / CLOCKS_PER_SEC);
}
long add2(long n)
{
	return n * (n + 1)/2;
}
void AddTime2(long n)
{
	clock_t t;
	long sum;
    t = clock();
    sum = add2(n);
	t = clock() - t;
	printf("方法2:\n");
	printf("  结果:1～%d之和:%ld\n", n, sum);
	printf("  用时:%lf秒\n", ((float)t) / CLOCKS_PER_SEC);
}
int main()
{
	int n;
	printf("n(大于1000000):");
	scanf("%d", &n);
	if (n < 1000000) return 0;
	AddTime1(n);
	AddTime2(n);
	return 1;
}